1. Field of the Invention
The present invention relates to a scratch-resistant thin film with a cured coating, and more particularly, to an optical thin film applicable to the backlight module in a liquid crystal display (LCD).
2. Description of the Prior Art
Since a liquid crystal panel does not emit light itself, a backlight module, as a brightness source, is an important element for the displaying function of LCDs, and is very important for enhancing the brightness of LCDs. Presently, various optical films are used in the backlight module, and the use of such various optical films has become the most economical and convenient solution to enhance the brightness of an LCD panel to optimize the service efficiency of the light source without altering any element design or consuming additional energy. FIG. 1 is a schematic diagram of various optical films contained in a backlight module. As shown in FIG. 1, the optical films contained in a common backlight module include: a reflective film (1) disposed below the light guide plate (2); and other optical films disposed above the light guide plate (2), i.e., from the top to the bottom, a diffusion film (3), brightness enhancement films (4) and (5), and a protective diffusion film (6) in sequence.
In recent years, a new technique using a V-cut light guide plate has been developed in the field of backlight modules, which is a popular technology in the field of the backlight modules for the panels used in current notebook computers. The V-cut light guide plate is made mainly by directly micro-fabricating a prism on a light guide plate, and is used in the backlight module in combination with a prism sheet (reverse prism sheet) with downward serration, thereby replacing the two prism sheets with upward serration in conventional backlight modules. FIG. 2 is a schematic diagram of a backlight module having a V-cut light guide plate. As shown in FIG. 2, the V-cut technique mainly employs one reverse prism sheet (9), and one V-cut light guide plate (8) and one reflective film (7) under the reverse prism sheet, and additionally a diffusion film (10) above the reverse prism sheet (9). Compared with the conventional backlight module, the brightness of the backlight module having a V-cut light guide plate can be enhanced nearly by 30%, and thus the required power can be reduced by one third, which is considerably beneficial to the improvement on power-saving performance.
Technically, due to optical properties, the structure of the reverse prism sheet tends to generate bright-and-dark stripes, and the reverse prism sheet has a brightness uniformity of about 75%, which is lower than the 85% uniformity conventionally obtained. Therefore, there is a need for a technical solution to remove the stripes and reduce the warp of the film caused by an ultraviolet curable coating on a single side and the V-shaped structure of the film itself.
In view of the above, the present invention provides a scratch-resistant thin film to overcome the above-mentioned shortcomings. In the present invention, a novel hard coat solution is used to form a scratch-resistant layer on the surface of a substrate having an opposite micro structured layer on the other surface. After curing, the scratch-resistant layer can improve the hardness of the thin film, and has a certain extent of light-diffusing effect, that is, it has a haze of 30% to 98% as measured according to JIS K7136 standard method, thereby the problems associated with the bright-and-dark stripes and low brightness uniformity encountered by the reverse prism sheet can be solved effectively.